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-rw-r--r--kernel/sched/isolation.c241
1 files changed, 241 insertions, 0 deletions
diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
new file mode 100644
index 0000000000..373d42c707
--- /dev/null
+++ b/kernel/sched/isolation.c
@@ -0,0 +1,241 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Housekeeping management. Manage the targets for routine code that can run on
+ * any CPU: unbound workqueues, timers, kthreads and any offloadable work.
+ *
+ * Copyright (C) 2017 Red Hat, Inc., Frederic Weisbecker
+ * Copyright (C) 2017-2018 SUSE, Frederic Weisbecker
+ *
+ */
+
+enum hk_flags {
+ HK_FLAG_TIMER = BIT(HK_TYPE_TIMER),
+ HK_FLAG_RCU = BIT(HK_TYPE_RCU),
+ HK_FLAG_MISC = BIT(HK_TYPE_MISC),
+ HK_FLAG_SCHED = BIT(HK_TYPE_SCHED),
+ HK_FLAG_TICK = BIT(HK_TYPE_TICK),
+ HK_FLAG_DOMAIN = BIT(HK_TYPE_DOMAIN),
+ HK_FLAG_WQ = BIT(HK_TYPE_WQ),
+ HK_FLAG_MANAGED_IRQ = BIT(HK_TYPE_MANAGED_IRQ),
+ HK_FLAG_KTHREAD = BIT(HK_TYPE_KTHREAD),
+};
+
+DEFINE_STATIC_KEY_FALSE(housekeeping_overridden);
+EXPORT_SYMBOL_GPL(housekeeping_overridden);
+
+struct housekeeping {
+ cpumask_var_t cpumasks[HK_TYPE_MAX];
+ unsigned long flags;
+};
+
+static struct housekeeping housekeeping;
+
+bool housekeeping_enabled(enum hk_type type)
+{
+ return !!(housekeeping.flags & BIT(type));
+}
+EXPORT_SYMBOL_GPL(housekeeping_enabled);
+
+int housekeeping_any_cpu(enum hk_type type)
+{
+ int cpu;
+
+ if (static_branch_unlikely(&housekeeping_overridden)) {
+ if (housekeeping.flags & BIT(type)) {
+ cpu = sched_numa_find_closest(housekeeping.cpumasks[type], smp_processor_id());
+ if (cpu < nr_cpu_ids)
+ return cpu;
+
+ return cpumask_any_and(housekeeping.cpumasks[type], cpu_online_mask);
+ }
+ }
+ return smp_processor_id();
+}
+EXPORT_SYMBOL_GPL(housekeeping_any_cpu);
+
+const struct cpumask *housekeeping_cpumask(enum hk_type type)
+{
+ if (static_branch_unlikely(&housekeeping_overridden))
+ if (housekeeping.flags & BIT(type))
+ return housekeeping.cpumasks[type];
+ return cpu_possible_mask;
+}
+EXPORT_SYMBOL_GPL(housekeeping_cpumask);
+
+void housekeeping_affine(struct task_struct *t, enum hk_type type)
+{
+ if (static_branch_unlikely(&housekeeping_overridden))
+ if (housekeeping.flags & BIT(type))
+ set_cpus_allowed_ptr(t, housekeeping.cpumasks[type]);
+}
+EXPORT_SYMBOL_GPL(housekeeping_affine);
+
+bool housekeeping_test_cpu(int cpu, enum hk_type type)
+{
+ if (static_branch_unlikely(&housekeeping_overridden))
+ if (housekeeping.flags & BIT(type))
+ return cpumask_test_cpu(cpu, housekeeping.cpumasks[type]);
+ return true;
+}
+EXPORT_SYMBOL_GPL(housekeeping_test_cpu);
+
+void __init housekeeping_init(void)
+{
+ enum hk_type type;
+
+ if (!housekeeping.flags)
+ return;
+
+ static_branch_enable(&housekeeping_overridden);
+
+ if (housekeeping.flags & HK_FLAG_TICK)
+ sched_tick_offload_init();
+
+ for_each_set_bit(type, &housekeeping.flags, HK_TYPE_MAX) {
+ /* We need at least one CPU to handle housekeeping work */
+ WARN_ON_ONCE(cpumask_empty(housekeeping.cpumasks[type]));
+ }
+}
+
+static void __init housekeeping_setup_type(enum hk_type type,
+ cpumask_var_t housekeeping_staging)
+{
+
+ alloc_bootmem_cpumask_var(&housekeeping.cpumasks[type]);
+ cpumask_copy(housekeeping.cpumasks[type],
+ housekeeping_staging);
+}
+
+static int __init housekeeping_setup(char *str, unsigned long flags)
+{
+ cpumask_var_t non_housekeeping_mask, housekeeping_staging;
+ int err = 0;
+
+ if ((flags & HK_FLAG_TICK) && !(housekeeping.flags & HK_FLAG_TICK)) {
+ if (!IS_ENABLED(CONFIG_NO_HZ_FULL)) {
+ pr_warn("Housekeeping: nohz unsupported."
+ " Build with CONFIG_NO_HZ_FULL\n");
+ return 0;
+ }
+ }
+
+ alloc_bootmem_cpumask_var(&non_housekeeping_mask);
+ if (cpulist_parse(str, non_housekeeping_mask) < 0) {
+ pr_warn("Housekeeping: nohz_full= or isolcpus= incorrect CPU range\n");
+ goto free_non_housekeeping_mask;
+ }
+
+ alloc_bootmem_cpumask_var(&housekeeping_staging);
+ cpumask_andnot(housekeeping_staging,
+ cpu_possible_mask, non_housekeeping_mask);
+
+ if (!cpumask_intersects(cpu_present_mask, housekeeping_staging)) {
+ __cpumask_set_cpu(smp_processor_id(), housekeeping_staging);
+ __cpumask_clear_cpu(smp_processor_id(), non_housekeeping_mask);
+ if (!housekeeping.flags) {
+ pr_warn("Housekeeping: must include one present CPU, "
+ "using boot CPU:%d\n", smp_processor_id());
+ }
+ }
+
+ if (!housekeeping.flags) {
+ /* First setup call ("nohz_full=" or "isolcpus=") */
+ enum hk_type type;
+
+ for_each_set_bit(type, &flags, HK_TYPE_MAX)
+ housekeeping_setup_type(type, housekeeping_staging);
+ } else {
+ /* Second setup call ("nohz_full=" after "isolcpus=" or the reverse) */
+ enum hk_type type;
+ unsigned long iter_flags = flags & housekeeping.flags;
+
+ for_each_set_bit(type, &iter_flags, HK_TYPE_MAX) {
+ if (!cpumask_equal(housekeeping_staging,
+ housekeeping.cpumasks[type])) {
+ pr_warn("Housekeeping: nohz_full= must match isolcpus=\n");
+ goto free_housekeeping_staging;
+ }
+ }
+
+ iter_flags = flags & ~housekeeping.flags;
+
+ for_each_set_bit(type, &iter_flags, HK_TYPE_MAX)
+ housekeeping_setup_type(type, housekeeping_staging);
+ }
+
+ if ((flags & HK_FLAG_TICK) && !(housekeeping.flags & HK_FLAG_TICK))
+ tick_nohz_full_setup(non_housekeeping_mask);
+
+ housekeeping.flags |= flags;
+ err = 1;
+
+free_housekeeping_staging:
+ free_bootmem_cpumask_var(housekeeping_staging);
+free_non_housekeeping_mask:
+ free_bootmem_cpumask_var(non_housekeeping_mask);
+
+ return err;
+}
+
+static int __init housekeeping_nohz_full_setup(char *str)
+{
+ unsigned long flags;
+
+ flags = HK_FLAG_TICK | HK_FLAG_WQ | HK_FLAG_TIMER | HK_FLAG_RCU |
+ HK_FLAG_MISC | HK_FLAG_KTHREAD;
+
+ return housekeeping_setup(str, flags);
+}
+__setup("nohz_full=", housekeeping_nohz_full_setup);
+
+static int __init housekeeping_isolcpus_setup(char *str)
+{
+ unsigned long flags = 0;
+ bool illegal = false;
+ char *par;
+ int len;
+
+ while (isalpha(*str)) {
+ if (!strncmp(str, "nohz,", 5)) {
+ str += 5;
+ flags |= HK_FLAG_TICK;
+ continue;
+ }
+
+ if (!strncmp(str, "domain,", 7)) {
+ str += 7;
+ flags |= HK_FLAG_DOMAIN;
+ continue;
+ }
+
+ if (!strncmp(str, "managed_irq,", 12)) {
+ str += 12;
+ flags |= HK_FLAG_MANAGED_IRQ;
+ continue;
+ }
+
+ /*
+ * Skip unknown sub-parameter and validate that it is not
+ * containing an invalid character.
+ */
+ for (par = str, len = 0; *str && *str != ','; str++, len++) {
+ if (!isalpha(*str) && *str != '_')
+ illegal = true;
+ }
+
+ if (illegal) {
+ pr_warn("isolcpus: Invalid flag %.*s\n", len, par);
+ return 0;
+ }
+
+ pr_info("isolcpus: Skipped unknown flag %.*s\n", len, par);
+ str++;
+ }
+
+ /* Default behaviour for isolcpus without flags */
+ if (!flags)
+ flags |= HK_FLAG_DOMAIN;
+
+ return housekeeping_setup(str, flags);
+}
+__setup("isolcpus=", housekeeping_isolcpus_setup);